Ultra-processed foods - those industrial products packed with additives - may have an unexpected effect on our muscles. A recent study reveals that high consumption is associated with fat accumulation in the thigh muscles, which could increase the risk of knee osteoarthritis.
This surprising discovery shifts our perspective on the role of diet in joint health.
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Researchers at the University of California, San Francisco examined 615 participants, average age 60, all at risk but with no signs of osteoarthritis at the start of the study. Over one year, they analyzed their diet, classifying about 41% of the foods consumed as ultra-processed. Common examples include sugary cereals, packaged snacks, soft drinks, and ready-to-eat meals.
The results, published in
Radiology, indicate that MRI scans of the thighs revealed fatty infiltration in the muscles, where streaks of fat gradually replace muscle fibers. This phenomenon, known as fatty degeneration, was more pronounced in those who consumed more ultra-processed foods, regardless of their total calorie intake.
The link persisted even after accounting for physical activity, weight, and other factors. Dr. Zehra Akkaya, lead author, notes that knee osteoarthritis is a growing global health problem, strongly linked to obesity and poor eating habits. This study demonstrates the importance of diet quality beyond simply counting calories.
Thigh MRIs of two women of similar age, BMI, and activity level. Woman B, with abdominal obesity and more ultra-processed foods, had more fat in her muscles than Woman A.
Credit: Radiological Society of North America (RSNA) The good news: reducing ultra-processed foods could protect muscle quality and lower the risk of osteoarthritis. Researchers emphasize that weight loss diets should pay more attention to food quality, not just calorie restriction. A balanced diet and regular physical activity remain the cornerstones of prevention.
This pioneering study, the first to use MRI to assess the impact of ultra-processed foods on muscle composition, paves the way for new strategies to combat knee osteoarthritis. By targeting modifiable factors like diet, we can hope to reduce the burden of this disabling disease.